The invention relates to a process for preparing neopentasilanes from polysilanes in the presence of ether compounds.
Neopentasilanes (tetrakis(silyl)silanes) are used for the deposition of Si—C in CVD processes.
The preparation of neopentasilanes is described in WO 2008051328. There, hexahalodisilane is reacted with tertiary amines as catalysts to form mixtures comprising tetrakis(trihalosilyl)silane. The tetrakis(trihalosilyl)silane is reduced with diisobutyaluminumhydride to form tetrakis(silyl)silane.
The process has the disadvantage that tertiary amines are frequently corrosive and must therefore be handled with care. Moreover, traces of nitrogen affect the semiconducting properties of silicon, and many applications therefore specify the nitrogen content.